This invention relates to the recovery of protic acids from a medium containing such acids. More particularly, this invention relates to a method of separating a protic acid from a medium and then recovering the protic acid in a usable form.
There are many processes wherein protic acids are generated. In most of these processes it is desirable to recover the protic acids. In certain processes, the protic acid is part of a waste stream and failure to recover the acid from the waste stream results in environmental damage. In other processes, the acid is a valuable chemical which can be used for further chemical processing, or can be recycled in the process. Thus, there is a need to recover such protic acids from waste streams or from reaction media. One common method is to contact the acid with an amine or a basic compound such as an alkaline earth metal base or alkali metal base, to form a salt. There are several problems with this kind of process. First, in some of these processes, it is very hard to have complete recovery of the acid from the system, as the salt formed may be hard to recover or not all of the acid reacts with the base. In the case of the use of alkali metal or alkaline earth metal bases, the halogen value cannot be recovered in usable form. When an amine is used to recover the acid the amine may decompose when one tries to recover the acid from the base. In such cases, it has been found that the dissociation conditions are more harsh than the conditions at which the amine used to recover the acid undergoes decomposition. In either case where the salt is lost, the acid is lost, or the amine undergoes decomposition before the acid can be recovered in the acid form significant cost penalties are paid.
What is needed is a process for the recovery of a protic acid from a medium containing such acid wherein the acid can be easily regenerated without loss or decomposition of the compound used to perform such recovery.